Prediction of pKas of Late Transition‐Metal Hydrides via a QM/QM Approach

Three implicit solvation models, the conductor‐like polarizable continuum model (C‐PCM), the conductor‐like screening model (COSMO), and universal implicit solvent model (SMD), combined with a hybrid two layer QM/QM approach (ONIOM), were utilized to calculate the pKa values, using a direct thermodynamic scheme, of a set of Group 10 transition metal (TM) hydrides in acetonitrile. To obtain the optimal combination of quantum methods for ONIOM calculations with implicit solvation models, the influence of factors, such as the choice of density functional and basis set, the atomic radii used to build a cavity in the solvent, and the size of the model system in an ONIOM scheme, was examined. Additionally, the impact of Grimme's empirical dispersion correction and exact exchange was also investigated. The results were calibrated by experimental data. This investigation provides insight about effective models for the prediction of thermodynamic properties of TM‐containing complexes with bulky ligands. © 2019 Wiley Periodicals, Inc. COSMO, C‐PCM, and SMD were utilized within the hybrid multilevel ONIOM approach to calculate the pKas of a set of transition metal hydrides in acetonitrile using a direct thermodynamic scheme. The influence of density functional and basis set choice as well as model layer size within the ONIOM method and other factors were examined and calibrated to experimental pKa values.